Presently (circa 2016) printers for three dimensional (3D) printer, such as FDM (fused deposition modeling) printers and FFM (fused filament modeling) printers suffer from a number of problems, particularly such smaller printers that are intended to operate upon a desk or tabletop. These problems lead to excessive setup times before 3D printing may be initiated, frequent downtime dealing with jams, cleaning, and/or re-calibration problems. Presently, these problems lead to reliability problems of 3D printing a given 3D object; and these problems lead to repeatability problems for 3D printing a same type of part over two or more production runs.
For example, present prior art extrusion chambers where a given portion of a filament is to be melted have insufficient temperature controls within the given extrusion chamber and problems in a filament pathway geometry through the given extrusion chamber. These problems with improper temperature control and improper filament pathway geometry lead to frequent and undesirable jams of filament material in the filament pathway within the given extrusion chamber. In prior art extrusion chambers, a hot end region is not properly sealed against liquid filament that cools, hardens, and results in blocked filament pathways, i.e., results in jams. That is, when a solid filament is liquefied in a melt chamber, some of this hot liquid filament material migrates upwards (due to pressure and density differentials in the filament material), and as this hot filament material that migrates upward, into cooler regions of the filament pathway, this material then cools, hardens, and creates blockages in the filament pathway. It would be desirable for an extrusion chamber to have proper temperature controls and proper filament pathway geometry to minimize jams and produce a controlled and consistent extrudate. It would be desirable for an extrusion chamber that minimizes and/or prevents against upward moving hot liquid filament material cooling and forming blockages.
Additionally, prior art filament feeding systems for FDM (FFM) printers also create problems. Presently these filament feeding systems grip and move the filament along via use of grooves, teeth, ribs, or knurling. Because filament materials are often softer than these grooves, teeth, ribs, or knurling, filament handling by such means encourages breakage of the filament resulting in downtime to reload the filament. Filament handling by such means also generates excessive filament dust and filament splinters which may clog various mechanical components, again resulting in undesirable downtime. Filament handling by such means also introduces imperfections to surface geometry of the filament, which may lead to jamming problems in the extrusion chamber and/or to inconsistencies in outputted extrudate. It would be desirable to handle movement of the filament in a way that does not encourage filament breakage, does not generate excessive filament dust or filament splinters, and that does not leave surface imperfections of the surface geometry of the filament.
Additionally, many prior art FDM (FFM) printers suffer from problems with slippage of extrudate and the receiving work surface. It would be desirable to layer extrudate upon the work surface in a manner with minimal slippage; yet, when the 3D printing run is done and the extrudate is hardened and/or cooled, that the 3D printed object may be readily removed from such a work surface without breaking the 3D printed object or without excessive intervening removal steps being utilized.
Additionally, many prior art FDM (FFM) printers suffer from tolerance stacking problems, particularly arising from how x-axis positioning systems, y-axis positioning systems, and z-axis positioning systems are attached to different and diverse structures within the prior art FDM (FFM) printers such that the cumulative tolerance stacking means those prior art FDM (FFM) printers must always have certain repeatability problems, requiring excessive calibration and/or alignment processes. In order to minimize such cumulative tolerance stacking problems, it would be desirable to minimize the different and diverse structures that the x-axis positioning systems, y-axis positioning systems, and z-axis positioning systems are attached to. In order to minimize such cumulative tolerance stacking problems, it would be desirable to utilize a common plane for attachment of the various axis positioning systems.
Similarly, prior art FDM (FFM) printers suffer from tolerance stacking problems associated with utilizing at least two z-axis guides; in that a mechanical fit between a given z-axis guides and its complimentary receiving sleeve must entail some level of mechanical fit tolerance; and for each such pairing of z-axis guide with complimentary receiving sleeve, cumulative tolerance stacking problems arise. Ideally, one wants a top surface (i.e., a working surface) of a build plate to be parallel with an x-y plane that the extrusion core moves in. However, in practice there must some degree of “wobble,” i.e., angles of offset between a plane of the top surface and the x-y plane. This wobble arises due to mechanical fit tolerances between z-axis guides and complimentary receiving sleeves that the given z-axis guides slides in. Prior art FDM (FFM) printers utilize two or more (e.g., two to four) such z-axis guides; and thus, two or more such complimentary receiving sleeves. Two or more z-axis guides are used, because if one z-axis guide was used, an expected location would be at a center of the build plate; however, locating a single z-axis guide at the center would also be in the center of the work surface and thus a centrally located single z-axis guide would get in the way of the printing. Thus prior art FDM (FFM) printers locate the z-axis guides off-center from the build plate; which then means the build plate may be acting as a lever arm upon an off-center z-axis guide; and to accommodate for that, prior art FDM (FFM) printers utilize at least two z-axis guides and sometimes three to four z-axis guides; which helps to distribute load from the build plate. But whenever two or more z-axis guides are used, the problem of mechanical fit tolerance stacking arises from each given z-axis guide and its complimentary receiving sleeve. The more z-axis guides, the more wobble. Wobble may be reduced by minimizing mechanical fit tolerances between the given z-axis guide and its complimentary receiving sleeve. But reducing such mechanical fit tolerances increases manufacturing costs. But even with reduced mechanical fit tolerances, there must be some mechanical fit tolerance; and thus tolerance stacking problems if two or more z-axis guides are used. Additionally, when two or more z-axis guides are used, an additional tolerance stacking problem is introduced with respect to a location of second or more complimentary receiving sleeves. Thus it would be desirable to minimize such mechanical fit tolerance stacking problems and utilize a single z-axis guide for the build plate.
There is a need in the art for a FDM (FFM) printer, which may be a desktop or tabletop printer, wherein the FDM (FFM) printer addresses these problems resulting in optimized reliability and repeatability of extrusion for progressive layering of extrudate to form a 3D printed object. That is, there is a need on the art for a FDM (FFM) printer that improves both reliability and repeatability of 3D extrudate layer printing.
It is to these ends that the present invention has been developed.